Agricultural revolution has helped mankind with new varieties of plants and bio fertilizers. Industrial revolution has given us lot of job opportunities by increasing the per capita income. Medical advances have increased our life span. Man is helping the society through his altruistic approach (to help others).

Water is an important abiotic component of an ecosystem. Water is a climatic factor and is not living.

A and E are not the features of hydrophytes. In hydrophytes, the cuticle is thin, epidermis is not well developed whereas in land plants, hypodermis is absent. The stomata are few or absent.

Gradual speciation species are formed due to genetic drift and natural selection.

All these are the immediate concerns regarding carbon cycle.

During the course of allopatric speciation, a part of the population become geographically isolated from the main population.

Both Assertion and Reasoning are true and related. Fertilizers like ammonium nitrites are prepared by this process.

Mercury interferes with brain function.

The environmental Protection Agency (EPA) has set the Maximum Contamination Level (MCL) of nitrates for the safety of drinking water. Nitrate levels at or above this level have been known to cause a potentially fatal blood disorder in, infants under six months of age called methaemoglobinemia or blue-baby syndrome, in which there is a reduction in the oxygen carrying capacity of blood.

Secretory organelles, which secrete enzymes to digest wood. The Protists inside the termites are Trichoflagellates, which secrete a digestive enzyme, cellulose, to digest cellulose. When these enzymes are lost, the termites can not digest wood.

Wild animals like tigers and lions mark their territory by their urine.

This gas causes respiratory problem as it has a strong affinity for haemoglobin.

Endemic population is the population confined to a particular area.

Spatial distribution of individuals in a particular place is called a population dispersion.

Subsere includes a secondary series of ecological communities, which begins after the interruption of succession by fire, grazing, agriculture, or any other destructive agent.

According to the law of population growth, given by P. F. Verhulst, the rate of increase in a population per unit time depends on the population size, the innate capacity to increase and the  unutilized opportunity for population growth. He defined it with a formula – dN/dt = rN where N is the number of individuals in a population, dN/dt is the rate of change of its numbers, over time and r is the intrinsic rate of natural increase in a population.

I-131 damages WBC and bone marrow.

Alpine meadows are seen where sediments, from the weathering of rocks, have produced soils, which are developed enough to support plants like grasses and sedges.

The United Nations conference on environment and development is also known as the Rio summit or the earth summit. This was a major United Nations conference held in Rio de Janeiro from June 3 to June 14, 1992. 172 governments participated, with 108 sending their heads of state or government.

Ozone layer thinning in the stratosphere increases global warming due to the penetration of UV rays through the ozone layer.

The rate of total capture of energy or the rate of total production of organic material is gross primary productivity while the balance or biomass remaining after meeting the cost of respiration of producers is net primary productivity. Hence, gross productivity has the highest value in grass land ecosystem.

Cline – Transient population between species having same genotypes and species having different genotypes.  Biotype - Group of individuals of a species having same type of genotype.  Ecotype - Genetically different populations of a species colonizing different specific habitat. Deme - It is an assemblage of closely related interbreeding individuals of a species.

In Abyssal zone - Bioluminescent organisms are exist. 

A, B and D are true of elephants and humans.  Both are K strategists according to population ecologists, i.e.,  they produce limited offsprings during their life spans. Elephants and humans show a long gestatation period during pregnancy and also show long fertile period in their life time.

Nitrification involves oxidation of nitrogen compounds.  The decomposers carry out a process called deamination which results in the release of ammonia. Ammonia undergoes oxidation to give nitrates.

Food industry produces putrefied organic matter.

These are the features of planktons. They are drifting organisms having no locomotory organs and they are mostly pelagic plants

The rate of energy storage at consumer level is the energy utilized by the consumer for the physiological activities (assimilation).